Changing your meal times by as little as an hour could be the key to losing weight and even reducing the risk of a heart attack, an experiment suggests.

Having breakfast later and supper earlier led to levels of body fat, cholesterol and blood sugar plunging within weeks, tests showed.

The research also demonstrated the risks of late-night fridge raids, with levels of fat and sugar in the bloodstream continuing to soar for hours during the night when you snack close to bedtime.

The study - carried out for the BBC show Trust Me, I’m a Doctor - set out to test the importance of altering not what you eat but when you eat it, after encouraging results in experiments on mice and flies.

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His belief that a shorter ‘feeding period’ and a longer span spent fasting helps shift weight and boost health was borne out in the tests.

The results showed that those who spent less time eating throughout the day had lower body fat, cholesterol and blood sugar – all key risk factors for cardio-vascular problems and diabetes.

In another test a traditional fry-up was consumed both in the morning and late in the evening.

After eating the meal in the morning, blood sugar levels returned to normal within two hours – far quicker than when eaten at night.

When we eat late at night, the already high levels of fat and sugar in the blood are sent into overdrive, which could have negative health impacts

Experts suspect this is due to the natural release of fat and sugar associated with the hormone melatonin, which tells the body to go to sleep.

When we eat late at night, the already high levels of fat and sugar in the blood are sent into overdrive, which could have negative health impacts.

Dr Johnston said: ‘Your body isn’t expecting you to be eating at that time of the day.

‘It is expecting you to be fasting and so what you find is that during that time when people eat a meal the spike of things like sugar and fat... is higher if you eat at night and that spike takes a bit longer to get back down to background level.

‘So if you eat most of your calories certainly during the early part of the day, and fewer calories in the late afternoon and the evening that will actually help your metabolism and potentially help you to lose weight and maintain weight loss as well.’

In good news for people with a hectic lifestyle, you do not have to squeeze together your mealtimes every day in order to feel these benefits - the occasional day of condensed eating can be enough to make an impact.

Dr Johnston noted: ‘If these effects can be maintained over time, then potentially they have very important benefits.’